Development of
Tectonically-Confined Submarine Fans from the
Hodgson, David M.1, Kevin T.
Pickering2 (1) University of Liverpool, Liverpool, United Kingdom
(2) UCL (University Colege London) Earth Sciences Dept, London, United Kingdom
A study of late Tortonian deep-water
systems in the
Deposits on the downstream flanks of
anticlines are coarse-grained (cobble-grade), with common deep scours surfaces,
regular concentrations of (fine-grained) rip-up clasts, and widespread
development of steep cross-bedded sediments. Onlap of sandstones onto
intrabasinal slopes are also common. In the centre of synclines at the same
stratigraphic interval, the sediments are fine-grained, paleocurrents are less
focussed, and evidence of rapid deposition (dewatering) is common. The
repetition of similar facies associations at similar geographic positions
across different structures is interpreted to indicate the occurrence of
headward incision through filled up-dip depocentres as sediment-laden flows
encountered steeper topography on downstream flanks. This study shows the
importance of understanding the impact of seabed topography on sediment-laden
density currents in order to aid subsurface exploration.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California